Fine needle aspiration (FNA) is a diagnostic biopsy procedure used to obtain a sample from a target site in a patient body. A fine needle (e.g., 19-gauge to 25-gauge) is directed to a target site, and suction is applied to the proximal end of a lumen of the needle to aspirate cells through its distal end. The procedure typically is far less invasive than other biopsy techniques, whether performed percutaneously (e.g., to sample a suspected breast tumor or subcutaneous lesion) or endoscopically (e.g., to sample a suspected cholangiocarcinoma via a duodenoscope). Moreover, advances in endoscopic ultrasound (EUS) technology have helped physicians and patients by providing enhanced ability of a physician to visualize a biopsy needle to obtain a sample of material from a target site without requiring an open incision or use of large-bore needles and/or laparoscopic trocars.
Current FNA techniques typically obtain only a small number of cells useful for diagnostic evaluation. As a result, this technique includes a risk of false negatives where the few cells obtained in a sample do not accurately represent the presence of a tumor or other disease condition. The small sample size may also limit the diagnostic value of the procedure if the cells obtained are sufficiently few in number or sufficiently damaged during collection that they do not enable a definitive diagnosis. Accordingly it would be advantageous to provide a needle useful for EUS and/or percutaneous FNB (fine needle biopsy) that can obtain a larger sample size (e.g., a larger number of cells in the sample or a “core” comprising intact adjacent cells held together in similar form to their native location, suitable for histological analysis) without requiring a larger-gauge needle or requiring multiple passes of the needle to reliably obtain a diagnostically efficacious sample with regard to the number and integrity of the cells in the sample. It would also be advantageous for the needle to be constructed in a manner providing for efficient operation through an endoscope such as a side-viewing gastric endoscope (also known as a duodenoscope), including ready navigation through the curvature(s) commonly required in using such an endoscope with a minimum of time and manipulation required.